Last video, we saw how to draw dot structure of molecule with single covalent bonds. this video will talk about multiple covalent bonds. so we start in the same way with the last video i want to draw the dot structure for C2H4 i would find carbon over here and once again carbon is in Group 4, so it has 4 valence electrons. so i'm going to go ahead and put in one carbon with four valence electrons and i know i have another carbon in my dot structure. it also has four vlence electrons like that so immediately i can see there is going to see a single covalent bond between my two carbons like that for hydrogens, and i know that hydrogens is in Group 1 on our periodic table, hydrogen hass one valence electron. now it makes sense and go ahead and put two hydrogens on each carbon so if i put one hydrogen over here and then another hydrogen on this carbon i have two more hydrogens so i can go ahead and put two hydrogens in the carbon on the right when i connect my dots, i can see that i have a bond between carbon and the hydrogen here. and this is not the correct dot structure. because if you count of the number of electrons around the carbons, let's go ahead and do it. let's do the carbon on the left i'm going to get two, four, six and seven electrons so it only has seven electrons around each carbon carbon does not satisfythe octet rule so the only way for the carbon to get the octet of the electrons around it, it would be this magenta electron moved in here and this electron mobves in here to form a double-covalent code